Means for turning control shafts to predetermined angular positions



2,163,343 MEANS FOR TURNING CONTROL SHAFTS T0 PREDETERMINED ANGULAR POSITIONS June 20, 1939. 7 LE ROY J. LEISHMAN Filed July 21, 1957 2 Sheets-Sheet l /N I/E N TOR.

LE ROY J. LEISHMAN June 20, 1939. 2,163,343

MEANS FOR TURNING CONTROL SHAFTS TO PREDETERMINED ANGUL-AR POSITIONS Filed July 21, 1937 2 Sheets-Sheet 2 n "1 trrrrn llll INAVE/VTOR:

Patented 20, 1939 PATENT. OFFICE MEANS FOR TURNING CONTROL SHAFTS TIONS PREDETERMINED AN GULAR POSI- Le Roy J. Lelshman, Los Angeles, Calif.

Application July 21. 1937, sci-m No. 154,819

11 Claims.

The invention herein described relates to improvements in automatic or semi-automatic apparatus for turning rotatable objects. about their axes to predetermined positions and more particularly to means whereby a plurality of such objects may be immediately and simultaneously rotated to any one of several pro-selected positions or settings which may be different for each rotated object.

The purposes of-this invention are to provide 7 simple apparatus for turning dials, shafts and the like to the particular settings required in using an instrument or machine for a definite task; to afford means whereby a plurality 02 such rotatable elements may be simultaneously turned each to a pre-selected position which may be different from that to which any other such element is being turned; to provide a simple manually operated control for accurately returning such rotatable elements to any desired previous position; to provide mechanism whereby a single manual operation will cause a plurality of rotatable members each to be turned to any one of a group of television makes it possible to tune in" a radio broadcasting station and its associated television broadcasting'station in far less time and with much less bother than would otherwisebe required.

The large number of pictorial elements needed in television for the transmission of a single detailed image within the time period of the persistence of vision, makes the use of short waves desirable; and further, the governments of various countries have allotted certain frequencies in the short wave bands for thispurpose. For these and other reasons, the satisfactory transmission of both sound and vision by radio waves requires that they be transmitted on difiereni' carrierfrequencies. To receive both the sound and the associated television, the radio receiving set must be turned to the frequency on which the radio broadcasting station is transmitting, and the short wave television receiver must be tuned to the diiferent frequency of the television broadcasting station which transmits the images of the scene at which the radio program originates. The dial settings for these stations are entirely different, and it is therefore impractical to turn the dials synchronously by any connecting means, such as gears, belts or a common shaft. The present invention makes it possible to accomplish this double tuning by a single manual operation.

Still other objects of this invention will be evident as the description'proceeds.

In the accompanying drawings:

\ Fig. 1 is a side elevation,'with certain parts cut away, of one embodiment of this invention, and shows two positions of an angularly positionable member and the associated manually operable positioning lever.

Fig. 2 shows an angularly positionable member in a position 180 degrees from that shown in full lines in Fig. 1, and in dotted lines the same member is shown after being rotated 90 degrees to the "tuned-in position. i

Fig. 3 shows two independently positionable members and a modified manually operable lever for moving them.

Fig. 4 shows the parts pictured in Fig. 3, with the lever pushed down to bring them both to the tuned-in position.

Fig. 5 illustrates how the modified positioning lever shown in Figs. 3 and 4 engages two positionable members simultaneously.

Fig. 6 is a plan view of an assembly in which a plurality'of positionable members are used to tune-in any one of a group of pre-selected radio broadcasting stations with its associated television station. Many parts have been omitted to facilitate an explanation of the structure and its operation.

Fig. 7 illustrates a method for eliminating play between the teeth of gears connecting the semiautomatic tuning mechanism with an independent tuning shaft.

' Fig. 8 pictures a plurality of positionable elements on the same shaft, showing the relationship with associated components. I

beFig. 9 is a modified form of positionable mem- Fig. 10 shows a pair of independently positionable members whose upper edges cannot be made to lie in the same plane due to inaccuracies of hole Z in projection X. Element A is so consetting the dials or controls of many difle'rent kinds of apparatus, its application to the automatic tuning of radio and television sets, as disclosed herein, may be considered as representative of its use for other purposes.

A preferred form of my invention, designed to turn a single control shaft to a predetermined position, is illustrated in Fig. 1. In this arrangement, S is the control shaft, and A is a positionable element or lever mounted on shaft 8 and held in position by set-screw R passing through structed and shaped thatthe downward movement of manually operable lever F will cause the element to be turned to the position shown in dotted lines.

As will be shown further on in this specification, a plurality of positionable elements may be mounted on shaft S, thus requiring a plurality of positioning levers like manually operable lever F. In order to accommodate these extra levers, the fulcrum Q of lever F is preferably a rod running parallel to shaft S. Lever F has a hub H to keep it from wobbling on rod Q, and is so located on rod Q that it turns in the same plane as its associated positionable element A. Lever F is held in an inoperative position by spring J attached to rod Q2. The upward movement of lever F is limited by resilient tube B around rod Q3.

The straight arm of element A has a projection W to prevent lever F from striking setscrew R. When lever F is pressed down, it strikes projection W which slides along the edge of the lever until the long, flat edge of element A and the lower edge of lever F both lie in the same plane. Further movement of these parts is then prevented by the fact that the long edge of element A extends on opposite sides of shaft S, and the downward movement of. one end of the element would therefore cause the upperward movement of the other end, which is prevented by the lever.

In Fig. 2, element A is shown in an angular position 180 degrees from that illustrated in Fig. 1. In this position, the end W of element A must rise in order to bring the element to the angular position shown in dotted lines. This necessary movement requires the downward motion of the curved end K of element A. This end is so shaped that when the element is in any position between those shown in full and dotted lines, the downward movement of lever F against curved end K will be at such an angle that end K will be forced down until element A takes the position shown in dotted lines.

It will be evident from Figs, 1 and 2 that if element A is found in any position between that shown in full lines in Fig. 1 and that pictured in full lines in Fig. 2, the downward movement of lever F will turn the positionable element to the tuned-in" position indicated in dotted, lines in both of these figures. This fact makes it possible to use thismechanism to turn shaft S precisely to a desired angular position by having the shaft in the desired position and the element in the position shown in dotted lines when the setscrew R is initially tightened, as will be explained in detail later.

Fig. 3 illustrates a modification. of my invention by means of. which two or three positionable elements may be independently turned to predetermined positions simultaneously. Element A is mounted on shaft S as in Figs. 1 and 2. Next to element A on this shaft is a bushing P, in-

sides of which the shaft is free to turn. Mounted on bushing P is an element C, which is identical to element A with the exception of the fact that it has a hole large enough to accommodate bushing P. Element C is held in a definite angular position on bushing P by means of setscrew T.

As shown in Fig. 6, a number of bushings or collars? may be held together to turn as a unit by means of a yoke Y attached to each bushing. Bushing P2 extends through support I0, and is attached by means of screw II to the shaft l2 of television tuner l3. It will be seen that the bushings, the yoke that holds them together, shaft l2 and tuner It all turn as a unit.

When two or more positionable elements are.

to be positioned by a'singlepositioning lever, the lever is provided with a broad base L, Figs. 3, 4, 5 and 6. Fig. 5 illustrates how the base L of such a lever extends into the planes of elements A and C to engage them both. An examination of Fig. 3 will make it clear that both elements shown (1. e., A and C) will turn to the position pictured in Fig. 4 when lever F is pressed down.

If three elements are to be positioned by a single lever, the third element is also mounted upon a bushing which may be joined to other similar bushings by a yoke similar to that just described. Such a. second yoke must move in the space between panel D, Fig. 4, and yoke Y. As one end or the other of various elements also move in this space, the yoke must have a deep enough throat to clear them. Two yokes, however, cannot pass each other. This limits their movement to perhaps degrees. If this is not suficient movement for the control shafts attached to these yokes, the movement may be increased by means of gears or other devices. When only one yoke is used-that is, when only two shafts are to be positionedthe various rotatable parts are capable of a maximum movement of degrees in either direction.

In the preferred embodiment of this invention, the instrument is provided with a panel, escutcheon or cover-plate D, Figs. 1 and 6, and the plate D has a slot G through which lever F protrudes. This slot is long enough to permit the free movement of lever F between the positions indicated in Fig. 1. The escutcheon is also provided with a hole U, through which set-screw R is accessible when element A is in the position shown in dotted lines. An index-tab'holder M is fastened to escutcheon D by means of pins or screws V suitably located as shown in Fig. 6. This indextab holder is preferably divided into compartments E as indicated in Figs. 1 and 6, and each compartment is adapted to hold an index-tab 0. The index-tab holder is provided with a window N, Fig. 1, for each index-tab or compartment. If this invention is being used to position two shafts simultaneously, such as the tuning shafts of a. regular broadcast receiver and a television receiver, each compartment or recess E is constructed wide enough to accommodate an index tab that will cover two holes U through which set-screws R and T of an associated pair of elements A and C may be reached. If the invention is used to turn a single shaft to any one of a group of predetermined positions, as is required in the case of the tuning shaft of a broadcast receiver, each tab covers one U hole only, and the tabs,'compartments and windows are consequently narrower.

In the following explanation of the method used to set this shaft-positioning device, it will be considered that the invention is being employed as an automatic tuner for a pair of radio .receivers designed respectively for sight and sound reception on unrelated carrier-frequencies. The index-tab O is first removed from the recess E beneath the lever F that the operator desires shall tune-in a particularpair of associated stations. This may be done by inserting the tip of the finger or the rubber on the end of a pencil through the window N, Fig. 1, and pressing on the tab while raising it out of the compartment.

Lever F is then pressed down, thus bringing the positionable elements to the tuned-in position indicated in full lines in Fig. 4 and in dotted lines in Figs. 1 and 2. While the lever is being held down to maintain the positioning elements in this position, a screw driver is inserted through window N, Figs. 1 and 4 and hole U, Figs. 1, 4 and 6,'into one of the set-screws, say R, Fig. 6, and the screw loosened. This permits shaft S to turn freely within the element. The desired radio station is then tuned in manually by means of knob 9 on shaft 6 of radio tuner I. Shaft 6 also carries a gear 4, attached to the shaft by screw 5. Gear 4 meshes with gear 2, aflixed to shaft S by screw 3. (Play is eliminated between the teeth of these gears by an arrangement to be described later.) It will thus be seen that shaft S has a definite angular position for each station to which tuner I may be tuned. After the station desired has been accurately tuned in, set-screw R. is again tightened. Set-screw T is then loosened while the associated television station is tuned in by means of knob ll attached to shaft [5 which turns drumtype tuning scale I6 and shaft H in any of the ways well known in the art and therefore neither illustrated nor described here. Shaft l2 rotates all the parts connected thereto, which includes the tuner l3, bushing P2, yoke Y, the various other bushings P and the positioning elements C whose set-screws are tightened. The

bushing turns freely, however, within the element C whose set-screw T has been loosened. After the desired television station has been tuned in as perfectly as possible, set-screw T is again tightened. Lever F is now released, and spring J, Fig. 3, returns it to rest against bumper-tube B. The positionable elements, however, remain in the position indicated in Fig. 4. Regardless of any subsequent angular position of shaft S and bushing P, a downward stroke of the associated lever F will return both positionable elements and the rotatable parts to which they are connected to the particular angular positions that they occupied when the original setting operation took place.

If a tuning device is connected to an angular positioning mechanism or calibrated scale by means of gears, any play between the gears makes it impossible accurately to transmit a definite angular position of the mechanism or scale to the tuning device. Expedients that have been used in the past to prevent this have included tightly fitting gears, or else a split gear on one shaft, the two halves of the gear having springoperated means for causing the teeth of the two halves either to bite the teeth of the gear on the other shaft or to spread between the teeth of the latter gear. Either of these methods of eliminating play between the teeth produces a great deal of friction and makes the mechanism hard to turn. The present invention uses a novel arrangement for eliminating play without increasing friction between the gear teeth, and its operation is such that it serves the additional purpose of counterbalancing the positioning elements. Unless otherwise unnecessary weight is added to the K end of the positioning levers, the end hearing the set-screw is much heavier, and if several of them are carried by shaft S, a lever is noticeably harder to press when the shaft is being turned in a direction that raises the heavy ends of the elements than when the heavy ends are being lowered. This fact is made use of in the arrangement illustrated in Figs. 6 and '7 for eliminating play in the gears. Spring 8, wound around shaft 6, is fastened at l8 to turn with the shaft, and the other end of the spring is fastened at I! L0 an immovable support l9, Fig. 6, attached tov bracket in by screw 20. Spring 8 has suflicient tension to turn shaft 6 and tuner I as far as they will go in the direction indicated by the arrow on gear 5, but is prevented from doing so by the weight of the heavy ends of elements A plus the friction encountered by shaft S. The result is that the teeth of gear 4 always presson-the same side of the teeth on gear 2, as clearly indicated in the modified arrangement illustrated in Fig. 7, thus eliminating play and counterbalancing elements A.

In addition to illustrating various features already described, Fig. 6 shows certain structural details that contribute toward' the satisfactory operation of a combined television and sound tuner. Many parts of the complete apparatus, however, havebeen omitted for the sake of clarity.

, Wherever the entire side of a positioning element would otherwise touch an adjacent member, the

positioning element is provided either with a short hub or spacing washer 2|. A wider spacer II is shown on rod Q between one lever and the hub of the next lever. Such spacers are of course used between all the levers, but only two levers are shown in the drawing, as the inclusion of all the parts would obscure various details.

When the tuner is designed to position one control shaft only, positioning elements A are of course spaced only by their narrow hubs, or thin spacing washers 2!, as illustrated in Fig. 8, and the operating levers are positioned on rod Q so that they strike in the center of the positioningelements, as indicated by lever F in Fig. 8, which is shown pressing against the upper surface of positioning element Al in the tuned-in position with spring J extended. This figure shows positioning element A2 in the position indicated in full lines in Fig. 1, and positioning element A3 is shown in the position illustrated in full lines in Fig. 2.

It is, of course, unnecessary that the-positioning elements have a continuous surface from projection W to the end of the curved portion K. Various modifications may suggest themselves, as for instance, the form shown in Fig. 9 which will function interchangeably with the types previously illustrated.

When two control shafts are to be positioned by the mechanism herein described, it is necessary that the holes in the A and C positionable elements be equidistant from the upper edges of the elements, or else only one of them can be perfectly aligned by the positioning lever. This condition is indicated in Fig, 10. The upper surface of positionable element A is shown in the same plane as the lower edge of lever F, but only one point on the surface of element C is in this plane. Lever C cannot be returned to an identical position each time lever F ispressed unless the lever strikes element C in at least two points,

When this condition does not prevail, the inaccuracy can be compensated for by using the arrangement illustrated in Figs. 11 and 12. The.

base L of the lever is split near the perpendicular blade of the lever proper, and the separation extends far enough back to permit the separated end 22 to be sprung from its normal position. The perpendicular blade of the lever proper has a projection 23, threaded to carry adjusting screw 24 which has a lock-nut 25. This screw may be screwed down until end 22 of base L touches the positionable element that is not making contact. When this condition has been attained, the lock-nut is tightened. Other forms of adjusting devices will suggest themselves; but if the positionable elements are cast in accurate forms, such expedients are unnecessary.

Various modifications may be made from the automatic tuning or positioning mechanism herein described, in the way of alteration or substitution of parts, or even the omission of certain components, without departing from the general nature or purpose of the invention.

My claims are:

1. In a mechanism for angularly positioning a control element of a radio device a combination including: a positionable member adjustably mounted upon a rotatable shaft, said member having a first arm extending on one side of said shaft and a second arm extending on the opposite side of said shaft, at least one of said arms having a curved portion extending a few degrees around said shaft; and a movable operating means adapted to engage one arm of said member and rotate it until the other arm engages said means.

2. In a mechanism for angularly positioning a control element of a radio device a combination including: a rotatable control shaft; a positionable lever mounted upon said shaft and having two arms extending on opposite sides of said shaft, one of said arms bearing a tightening screw extending from said shaft substantially to said arms free outer end; and a movable operating means adapted to engage either of said arms.

3. A combination including: a rotatable control shai t; a bushing mounted upon said shaft; a first positionable member adjustably mounted upon said shaft; a second'positionable member adjustably mounted upon said bushing; and a man.- ually operable positioning means having a T- shaped cross-section, the sides of the part corresponding to the top of the T each adapted to engage a different positionable member.

4. A combination including: a rotatable control shaft; a bushing mounted upon said shaft;

, a first positionable'member adjustably mounted upon said shaft; a second positionable member adjustably mounted upon said bushing; and. manually operable means adapted to engage both of said positionable members; each of said members having a first arm extending on one side of said shaft and a second arm extending on the opposite side of said.shaft, one of said arms having a curved end extending partially around said shaft.

5.'In a mechanism for angularly positioning a control for a radio device, a combination including: a positionable member adjustably mounted upon a rotatable shaft, said member having a plurality of lever arms, at least one of said arms having a peripherally curved surface; and an operating means for rotating said member, said means adapted to engage said lever arms and to apply pressure to said member on either side of tion to an angular position at which said means is engaged by a portion of said member lying on the opposite side of said shaft; said member rotatable from certain extreme positions of its possible angle of rotation by the application of pressure to said peripherally curved surface from portions of said operating means that are totally different from the portions that apply pressure to said member for rotating it in an opposite direction.

6. In a mechanism for angularly positioning a control for a radio device, a movable operating means; and a positionable member adjustablv mounted upon a rotatable shaft, said member having at least two lever arms; at least one arm of said member having a peripherallycurved surface adapted to be engaged by said operating means for rotating said positionable member to a position at which two points on opposite sides of said shaft are simultaneously in engagement with said operating means; said peripherally curved surface and said points lying in the same plane; said positionable member rotatable in opposite directions solely by the application of pressure to said member from totally different portions'of said means.

'7. A combination including: a movable operating means; a shaft substantially transverse to the plane of movement of said means; an escutcheon having an opening therein; a rotatable element mounted on said shaft, said element having two arms each adapted to be engaged by said operating means for rotating said element in a different direction to a predetermined angular position; a threaded member for tightening said element on said shaft; said threaded member being in register with said opening when said element is in said predetermined angular position; a cover for said opening; and means for holding said cover over said opening on the side of said escutcheon opposite from said threaded member.

8. In a devicev for operating a control for radio apparatus, a combination including: a rotatable member adjustably mounted upon a shaft, said member having arms extending on opposite sides of said shaft; and pivoted means adapted to engage one arm of said rotatable member near the free end of said means when said arm lies in the path of said means, and to engage the other arm of said rotatable member near the pivoted end of saidmeans when said latter arm lies in the path of said means.

9. In a mechanism for angularly positioning a control for a radio device, a combination including: an operating member mounted on a pivot; and a positionable member adjustably mounted upon a shaft and adapted to be engaged by said operating member for rotating said positionable member to a position at which two points on said positionable member lying on opposite sides of said shaft coincide with the adjacent edge of said operating member; one of said members having a curved edge extending between said shaft and said pivot when said points are in engagement with the edge of said operating member.

10. In a mechanism for selectively positioning a radio control, a combination including: a rotatable element; a plurality of manually movable station selectors; a plurality of angularly adjustable members each operatively interposed between one of said selectors and said element; each of said members having two arms each adapted upon movement of the associated selector toward said element to rotate said element in a diflerent direction to a position predetermined by the adjustment of said member; a plurality of screws each individual to one of said members for retaining said member in adjusted position and a plurality of removably mounted index tabs each individual to one of said selectors and to one of said screws, each of said tabs positioned so that its removal will expose the associated screw for adjustment purposes.

11. In a device for angularly positioning a plurality 01 control elements, a combination including: two pairs of arms, the arms in each pair adapted to-move reciprocally in opposite directions; a movable operating means adapted at one extreme of its movement to be substantially in contact with all i'o'ur arms; and means to eliminate play between one of said arms and said operating means.

' LE ROY J. LEISHMAN. 

